PCD5013H/F1 데이터 시트보기 (PDF) - Philips Electronics

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PCD5013H/F1

FLEX™roaming decoder II

Philips Electronics 

Philips Semiconductors

FLEX™ roaming decoder II

Product specification

PCD5013

8.4 Configuration and synchronisation

8.4.1 GENERAL

After a reset, all configuration data has to be (re)loaded

into the PCD5013 by the host using the SPI. PCD5013

features which do not change during operation are

configured using the configuration packet (Section 8.4.4),

the receiver control packets (Section 8.5) and the address

configuration packets (Section 8.6). PCD5013 features

which can be changed during operation are configured

using the control packet. The checksum packet ensures

proper communication between the host and the

PCD5013.

8.4.2 SPI SECURITY ALGORITHM

The PCD5013 provides a security algorithm to verify

correct SPI operation (Figs 9 and 10). The PCD5013

maintains a checksum register equal to the result of

XORing the 24 data bits of every packet it receives, except

the checksum packet 00H and special packets

1CH to 1FH. When the PCD5013 is reset, the internal

checksum register is initialized to the 24-bit part ID defined

in the part ID packet.

Immediately following a reset and whenever the host

sends a packet other than a checksum packet, the

SPI output of status and data (SPI transmit) is disabled.

The PCD5013 then initiates SPI transfers continuously,

sending the part ID packet (Section 8.4.5). Note that when

SPI transmit is disabled all decoding and timing functions

are unaffected. The SPI transmit can be enabled by

sending a checksum packet for which the checksum value

matches the checksum register.

Checksum packets sent when the SPI transmit is enabled,

are ignored by the PCD5013 irrespective of the value of

the checksum packet data bits. Thus when the PCD5013

initiates an SPI transfer and the host has no data to send,

the host should send the checksum packet so as not to

disable the SPI transmit. The data in the checksum packet

could be a null packet (32-bit stream of all zeros).

Sending a packet other than the checksum packet when

the SPI transmit is enabled causes the SPI transmit to be

disabled until a checksum packet is sent with the correct

value. Thus when the host re-configures the PCD5013

after a reset, the SPI transmit is disabled until the host

sends a checksum packet at the end of the configuration

data, with the checksum value equal to the result of

XORing together the data bits of each of the configuring

packets and the data bits of the part ID packet.

If the SPI transmit is enabled and a receiver shutdown

packet is pending, the receiver shutdown packet is sent. If

there is no receiver shutdown packet pending, but there is

a roaming status packet pending, the roaming status

packet is sent. If neither the receiver shutdown packet nor

the roaming status packet is pending and there is data in

the transmit buffer, the PCD5013 initiates an SPI transfer

sending a packet from its transmit buffer. The PCD5013

sends the status packet (which is not buffered) when the

host initiates an SPI transfer and the transmit buffer is

empty.

handbook, full pagewidth

32

PART ID REGISTER

32

RECEIVER SHUTDOWN REGISTER

32

ROAMING STATUS REGISTER

32 × 32 DATA PACKET

FIFO TRANSMIT

BUFFER

STATUS REGISTER

32

32

MUX

SPI TRANSMIT REGISTER

MISO

MGR618

32

SPI

SECURITY

ALGORITHM

Fig.9 SPI transmit functional block diagram.

1999 Apr 12

15

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